We put up with perennials—and their fleeting blooms—because we love the way they reappear, year after year. But with a bit of extra effort—namely, judicious pruning—the perennials here will offer a repeat performance. (If blossoms are allowed to fade, and stay on the plant, the whole plant moves out of the flowering phase and channels much of its energy toward seed production rather than green growth and blooms.) You can short-circuit the usual transition by deadheading at the stem. So without further ado, let us present the ultimate garden stars.